Phillip Phillips sings with John Fogerty: The still-unofficial winner and Creedence Clearwater Revival's front man started the show with a pitch-perfect performance of classics "Have You Ever Seen the Rain" and "Bad Moon Rising."
Joshua Sings with Fantasia Barrino: A favorite of the judges, the third-place finisher performed a growling rendition of Elton John's "Take Me to the Pilot" with "the biggest inspiration in my life," season 2 winner Fantasia Barrino.
Top 12 women perform with Chaka Khan: They may have gone home early but Hollie Cavanagh, Skylar Laine, Erika Van Pelt, Elise Testone and Shannon Magrane got to sing "I'm Every Woman" with the legend. Not too shabby!
Rihanna takes the stage: Rocking funky dreadlocks, the pop super star showed the newbies how to put on a show, stepping out of a boxed pyramid to perform her new single "Where Have You Been?" with a bevy of backup dancers, drummers, high-flying stilt walkers, smoke and lasers.
Skylar Laine sings with Reba: Mississippi's pride and joy – and season 11's sole country singer – took the stage with country icon Reba to sing the sassy hit "Turn on the Radio."
Mario Anzuoni / Reuters / Landov
Top 12 sing the phone book: After a montage of judge Randy Jackson telling contestants throughout the years who could and couldn't "sing the phonebook," Idol producers dug up some yellow pages so the top 12 (minus the finalists) could prove themselves worthy.
Jennifer Lopez performs The judge showed off her singing and dancing chops in a sparkling getup with two new songs that have never been performed on TV: "Goin' In" from the movie Step Up: Revolution and "Follow the Leader" with Wisin y Yandel.
Hollie Cavanagh sings with Jordin Sparks: The fourth-place finisher's duet with the season 6 winner could have been a diva-like belt-off if they both weren't so sweet and hadn't sounded so great together singing "You'll Never Walk Alone."
Jessica performs with Jennifer Holliday: Jennifer Hudson would be proud! Season 11's runner-up held her own against Broadway's original Dreamgirls star, Jennifer Holliday, while singing the chills-inducing anthem "And I Am Telling I'm Not Going." Wow!
Aerosmith performs: Ryan Seacrest said he waited two years to introduce judge Steven Tyler's band – but it was worth the wait! The rockers performed "Legendary Child," their first new song in six years, and "Walk This Way" on Wednesday's show.